One of the mites currently undescribed by science, discovered in the Upper Walbran canopy. Photo: Zoë Lindo
New Discoveries in the Ancient Forest Canopies
Some of the most remarkable discoveries of biodiversity in the world are being made right now by scientists studying the canopies of ancient forests on Vancouver Island. The decay of moss over centuries on the branches of ancient trees and the resulting formation of soil there - suspended high up off the ground - has created a type of habitat that is home to many newly discovered species. Scientists are only just beginning to scratch the surface of this incredibly diverse canopy ecosystem. These suspended soil layers don’t exist in the younger second-growth tree plantations, as they take hundreds of years to build-up on the wide limbs of giant trees.
Canopy researcher on the mossy Sitka Spruce limbs in the Upper Carmanah Valley, 1990. Photo: WCWC photo file.
Many conservationists are aware of the work of Dr. Neville Winchester, an entomologist (bug biologist) at the University of Victoria. Winchester’s doctorate thesis in the early 1990’s yielded the discovery of over 70 new species of arthropods - mites, spiders and insects - in the suspended moss/soil layers of just five old-growth Sitka spruce trees in the then-endangered Upper Carmanah Valley. Winchester’s study helped to raise public awareness about the biological uniqueness of these ancient forests and, along with a successful campaign by the Wilderness Committee resulted in the protection of the entire Carmanah Valley in 1994.
Now a professor at the University of Victoria, Winchester is supervising PhD student and mite expert, Zoë Lindo, who is embarking on a new comprehensive study in the spectacular ancient western red cedar canopies of the Castle Grove in the endangered Upper Walbran Valley. Because old-growth red cedars generally have a “pitch-fork top”, where their large branches curve upwards like giant vertical, pointy arms, they form deep “pockets” of moss and soil in between these “arms”. These moss pockets can contain soil layers as deep as 50 cm thick - even deeper than the soil on the ground
After one field season, Lindo has already made some incredible discoveries.
Zoë Lindo, UVic mite expert, is doing her research in ancient cedar canopies of the Upper Walbran’s Castle Grove. Photo: Zoë Lindo
Her preliminary research has yielded 54 species of Oribatid mites in the canopy of six cedar trees - an estimated one-fourth of which are still undescribed by science. Oribatid mites are a major component of mite fauna in soils and as they eat dead matter and fungi, they are important in decomposition and nutrient cycles.
19 of the 54 species were only found in the canopy and not on the adjacent forest floor, suggesting that canopy soils provide a habitat not found on the ground.
Why should we care about canopy mites and suspended soil? Mites are one of the most genetically diverse organisms on earth, with hundreds of thousands of species. They’re important in their own right, like all living things, and also as part of the ecosystems in aiding decomposition, in their predation of bacteria and fungi, and as food for many other organisms. What role they play in long-term forest health is currently unknown.
In addition, who knows how the suspended soils, their chemistry, and the new species of mites, insects, and bacteria living there could benefit humanity, such as new medicinal treatments or cures for diseases?
Unfortunately, the rapid conversion of Vancouver Island’s ancient forests into second-growth tree plantations that lack the canopy moss mats/ suspended soils, is undoubtedly exterminating countless species and biological communities even before we know of their existence.
